Castle Island Weather Forecast

    • 51
    • 64

    Increasing Clouds

    • 50
    • 64

    Mostly Cloudy

    • 51
    • 63

    Rain Likely

    • 48
    • 63

    Rain

    • 50
    • 63

    Partly Sunny

    • 51
    • 65

    Partly Sunny

    • 50
    • 64

    Partly Sunny

Today 22 May San Juan County

Mostly sunny in the morning then becoming sunny. Highs in the mid 60s to lower 70s. Light wind.

Tonight 22 May San Juan County

Partly cloudy in the evening then becoming mostly cloudy. Lows near 50. Light wind.

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  • Temperature Forecast NOAA

  • Temperature Real-Time

Castle Island Temperature Statistics

May Temperature

Whidbey Island Naval Air Station - Ault Field (8.1 miles)

  • Lowest 16 May, 2026

    44.1 °F

  • Average May

    53 °F

  • Highest 3 May, 2026

    66.9 °F

Climate (2021–Present)

Whidbey Island Naval Air Station - Ault Field (8.1 miles)

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  • Average Low 2021–2026

    44.5 °F

  • Average 2021–2026

    50.1 °F

  • Average High 2021–2026

    56.1 °F
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